66 FERTILIZERS. 



another layer of bones, with ashes, gypsum, loam or muck, 

 and water, as before, until the heap is built up several feet ; 

 finally cover with loam, and keep moist by adding water 

 from time to time, but not enough to run away from the 

 bed. When the bones are sufficiently softened, mix well 

 together with the loam used on the bed, and cover with 

 loam." Professor Johnson thinks this plan would require 

 more time, but perhaps would be as efficacious, and more 

 convenient than the process last described. 



Fifteen or twenty years I tried to reduce a lot of bones 

 by a method like this, except that some lime was used with 

 the ashes. The results were not satisfactory ; possibly the 

 lot was kept too moist. 



" A third method suggested is by inter-stratifying them 

 with fermenting horse-dung, and keeping the mass moist 

 by covering with loam, and adding occasionally urine or 

 liquor from the dung heaps." 



Professor Johnson make.s an estimate of the commercial 

 value of the product made by the Russian process : 



" Four thousand pounds of average bones contain 4 per 

 cent, or 160 pounds, of nitrogen, and 20 per cent, or 800 

 pounds, of phosphoric acid ; 4,000 pounds of good wood 

 ashes, unleached, contain 8 per cent, or 340 pounds, of 

 potash, and 2 per cent, or 80 pounds, of phosphoric acid. 

 Therefore 



" 160 pounds of nitrogen, worth 20 cents . . . $32 00 

 880 pounds of phosphoric acid, worth 9 cents . 79 20 

 380 pounds of potash, worth 5 cents . . . 18 70 



$129 90 



" Admitting that there is no loss of nitrogen, and no loss 

 or gain of water, and taking no account of the loam, the 

 value of $129.90 would belong to 13,100 pounds, or 6J tons, 

 of the finished lime compost. The cost of one ton would 

 accordingly be, in round numbers, 20." 



